A distinct difference in behavior is that OS X+ Finder has the ability to view the same folder in multiple windows, which is a necessity if you're going to keep the miller column view.
Classic Mac OS Finder did not allow this. Every time you opened a new folder, a new window would open. If you navigated to a folder already open, the previous window would jump to the front. That's how spatial Finder worked so well. It's difficult to combine both these patterns. It's one of the reasons people felt Mac OS "just worked" without necessarily being able to elaborate as to why.
Classic Mac OS Finder did not allow this. Every time you opened a new folder, a new window would open. If you navigated to a folder already open, the previous window would jump to the front. That's how spatial Finder worked so well. It's difficult to combine both these patterns. It's one of the reasons people felt Mac OS "just worked" without necessarily being able to elaborate as to why.